Rhizome extract of temulawak (Curcuma xanthorriza Roxb.) has residue properties derived from secondary metabolites. The metabolites inhibit the growth of plants, and it can be used as bioherbicide. Cyperus rotundus is a common weed that grows in soybean cultivation and it needs to be controlled. This research aimed to study the potential of temulawak rhizome extract on Cyperus rotundus and get temulawak rhizome extract concentration that can suppress the growth of Cyperus rotundus without inhibiting the germination of soybeans. The experiment was conducted on March to April 2015 and divided into three experiments. The first experiment was conducted in the Laboratory of Environmental Resource using completely randomized design. The second experiment and third experiments placed in Greenhouse UB Faculty of Agriculture, each using completely randomized block design and randomized block design. This study consisted of six treatments that were P0 (control), P1 (20% concentration), P2 (40% concentration), P3 (60% concentration), P4 (80% concentration), P5 (100% concentration) and four replications. The results showed that 20% concentration of temulawak rhizome extract can suppress Cyperus rotundus. Increasing concentration of temulawak rhizome extract up to 60% suppress growth of Cyperus rotundus. Temulawak rhizome extract significantly inhibited germination of soybeans at concentration of 60%.